@ Graham: No, i never used Grub Customizer
@ stephane:
$ sudo ls /etc/mkinitcpio.d/*.preset
/etc/mkinitcpio.d/linux510.preset /etc/mkinitcpio.d/linux58.preset
/etc/mkinitcpio.d/linux54.preset
$ sudo ls /boot/*
/boot/initramfs-5.10-x86_64-fallback.img /boot/intel-ucode.img
/boot/initramfs-5.10-x86_64.img /boot/linux510-x86_64.kver
/boot/initramfs-5.4-x86_64-fallback.img /boot/linux54-x86_64.kver
/boot/initramfs-5.4-x86_64.img /boot/vmlinuz-5.10-x86_64
/boot/initramfs-5.8-x86_64-fallback.img /boot/vmlinuz-5.4-x86_64
/boot/initramfs-5.8-x86_64.img /boot/vmlinuz-5.8-x86_64
/boot/grub:
fonts grub.cfg grubenv i386-pc locale themes
/boot/memtest86+:
memtest.bin